The present invention relates to a protective cover for an open zone of a machine tool or similar, in which there are machine moving parts within the area defined by said zone.
In particular, the cover is attached to a machining part or tool which moves along a respective operating path, preferably extending in accordance with at least two reference co-ordinates and, in particular, extending in a plane substantially parallel with the plane in which said area lies.
Such types of covers, described above, basically comprise a plurality of cover elements consisting of a set of substantially planar plates, closed together in a pack, and arranged one on top of the other in such a way that they make contact with one another. One of the plates is rigidly fixed along the edges of the machine which define the above-mentioned open zone, and acts as a support for the other plates, which slide relative to one another.
The perimetric dimensions of the fixed plate are such that it completely covers the open zone and has an opening which gives the plate the shape of a frame. The dimensions of the opening are substantially equal to the area in which the mobile tool is designed to move, defining the maximum travel possible for the tool along the two co-ordinates.
Starting with the fixed plate, the size of the remaining mobile plates decreases down to the last plate in the set, which is attached to the mobile tool. The shape of each plate is similar to that of the others and each has a respective opening, giving it a frame shape similar to that of the fixed plate. The outer and inner perimetric dimensions of a generic frame-shaped plate are similar to the outer and inner perimetric dimensions of the adjacent larger and smaller plates.
Each plate is kinematically connected to the others and its size complements that of the plates adjacent to it in such a way that, following a movement of the tool along the above-mentioned path, the plate attached to it draws behind it, in succession, the other plates, which slide over one another, keeping the area of the above-mentioned zone closed and protected during the tool operating movements. In this way, the cover allows protection of the machining tool support and drive parts extending towards the inside of the machine.
The drawing movements between the plates are transmitted by means of drive mechanisms, such as chains and corresponding toothed wheels, or four-bar linkages, with extremely complex and difficult operation, especially if the tool moves at relatively high operating speeds. Moreover, such types of mechanisms are not only costly and require long assembly times, but also make the covers heavy and too big.